Hybrid streetlights use and outwit Mother Nature

In its search for a reliable off-the-grid power source, the Chicago suburb of Downers Grove is the first in the nation to install streetlights powered by both the sun and the wind.

A vertical-axis wind turbine perched atop a concrete utility pole complements a 175 W solar panel placed directly above the 57 W luminaire. The EftsonScience Inc. system's controller ensures that the batteries that store the electricity generated by both sources, plus the sealed backup battery housed in the pole that provides up to three days of power, are neither over- nor under-charged. (To see a video of their installation, go to http://alturl/urcj.)

Placed 150 feet apart to provide standard photometrics, 25 of the futuristic-looking assets were installed last year in a formerly unlighted subdivision to provide full brightness from dusk until dawn. None of the turbines collected snow or ice buildup.

Almost half of the $282,500 project, which just received an award for technical innovation from the Chicago Metro Chapter of the American Public Works Association, was funded by a Community Development Block Grant.